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iconv: Accept redundant shift sequences in IBM1364 [BZ #26224]

Message ID 20201103205549.GA56271@aloka.lostca.se
State Superseded
Headers show
Series iconv: Accept redundant shift sequences in IBM1364 [BZ #26224] | expand

Commit Message

Arjun Shankar Nov. 3, 2020, 8:55 p.m. UTC
From: Arjun Shankar <arjun@redhat.com>

The IBM1364, IBM1371, IBM1388, IBM1390 and IBM1399 character sets
share converter logic (iconvdata/ibm1364.c) which would reject
redundant shift sequences when processing input in these character
sets.  This led to a hang in the iconv program (CVE-2020-27618).

This commit adjusts the converter to ignore redundant shift sequences
and adds test cases for iconv_prog hangs that would be triggered upon
their rejection.  This brings the implementation in line with other
converters that also ignore redundant shift sequences (e.g. IBM930
etc., fixed in commit 692de4b3960d).
---
 iconv/tst-iconv_prog.sh | 16 ++++++++++------
 iconvdata/ibm1364.c     | 14 ++------------
 2 files changed, 12 insertions(+), 18 deletions(-)

Comments

Florian Weimer Nov. 3, 2020, 10:03 p.m. UTC | #1
* Arjun Shankar:

> From: Arjun Shankar <arjun@redhat.com>
>
> The IBM1364, IBM1371, IBM1388, IBM1390 and IBM1399 character sets
> share converter logic (iconvdata/ibm1364.c) which would reject
> redundant shift sequences when processing input in these character
> sets.  This led to a hang in the iconv program (CVE-2020-27618).
>
> This commit adjusts the converter to ignore redundant shift sequences
> and adds test cases for iconv_prog hangs that would be triggered upon
> their rejection.  This brings the implementation in line with other
> converters that also ignore redundant shift sequences (e.g. IBM930
> etc., fixed in commit 692de4b3960d).

Can you update the news file as well?  Thanks.

Florian
diff mbox series

Patch

diff --git a/iconv/tst-iconv_prog.sh b/iconv/tst-iconv_prog.sh
index 8298136b7f..d8db7b335c 100644
--- a/iconv/tst-iconv_prog.sh
+++ b/iconv/tst-iconv_prog.sh
@@ -102,12 +102,16 @@  hangarray=(
 "\x00\x80;-c;IBM1161;UTF-8//TRANSLIT//IGNORE"
 "\x00\xdb;-c;IBM1162;UTF-8//TRANSLIT//IGNORE"
 "\x00\x70;-c;IBM12712;UTF-8//TRANSLIT//IGNORE"
-# These are known hangs that are yet to be fixed:
-# "\x00\x0f;-c;IBM1364;UTF-8"
-# "\x00\x0f;-c;IBM1371;UTF-8"
-# "\x00\x0f;-c;IBM1388;UTF-8"
-# "\x00\x0f;-c;IBM1390;UTF-8"
-# "\x00\x0f;-c;IBM1399;UTF-8"
+"\x00\x0f;-c;IBM1364;UTF-8"
+"\x0e\x0e;-c;IBM1364;UTF-8"
+"\x00\x0f;-c;IBM1371;UTF-8"
+"\x0e\x0e;-c;IBM1371;UTF-8"
+"\x00\x0f;-c;IBM1388;UTF-8"
+"\x0e\x0e;-c;IBM1388;UTF-8"
+"\x00\x0f;-c;IBM1390;UTF-8"
+"\x0e\x0e;-c;IBM1390;UTF-8"
+"\x00\x0f;-c;IBM1399;UTF-8"
+"\x0e\x0e;-c;IBM1399;UTF-8"
 "\x00\x53;-c;IBM16804;UTF-8//TRANSLIT//IGNORE"
 "\x00\x41;-c;IBM274;UTF-8//TRANSLIT//IGNORE"
 "\x00\x41;-c;IBM275;UTF-8//TRANSLIT//IGNORE"
diff --git a/iconvdata/ibm1364.c b/iconvdata/ibm1364.c
index 49e7267ab4..521f0825b7 100644
--- a/iconvdata/ibm1364.c
+++ b/iconvdata/ibm1364.c
@@ -158,24 +158,14 @@  enum
 									      \
     if (__builtin_expect (ch, 0) == SO)					      \
       {									      \
-	/* Shift OUT, change to DBCS converter.  */			      \
-	if (curcs == db)						      \
-	  {								      \
-	    result = __GCONV_ILLEGAL_INPUT;				      \
-	    break;							      \
-	  }								      \
+	/* Shift OUT, change to DBCS converter (redundant escape okay).  */   \
 	curcs = db;							      \
 	++inptr;							      \
 	continue;							      \
       }									      \
     if (__builtin_expect (ch, 0) == SI)					      \
       {									      \
-	/* Shift IN, change to SBCS converter.  */			      \
-	if (curcs == sb)						      \
-	  {								      \
-	    result = __GCONV_ILLEGAL_INPUT;				      \
-	    break;							      \
-	  }								      \
+	/* Shift IN, change to SBCS converter (redundant escape okay).  */    \
 	curcs = sb;							      \
 	++inptr;							      \
 	continue;							      \